Stubborn Head

I thought *I* was stubborn!! I'm working on re-heading a drum, and the old head is on so tight that I can't pull it off the drum--even after pulling all the tacks out! In fact, even after I pulled all the tacks out, the head sounds as good as it did before I pulled the tacks out! I can't, for the life of me, figure out how to get that old head OFF! Tonight I enlisted some help and we put the drum on the stretching rack and I used 4 hydralic jacks and 3/8" manila rope to try to yank that head off, but all to no avail. When we had the head cranked down, it was making all sorts of mean and impending-doom-sounds, but OMG--nothing. I hit it with a heavy mallet over and over (plus I hit my own hand too--NOT GOOD) but nothing. I can't think of anything so stubborn!

Help! Anyone have any experience with this? I might have to try putting it back on the stretching rack again and what--maybe apply some WD-40 on it? I have no idea. Until then, that's what I'm doing with my spare time.